RF MEMS tunable capacitors with large tuning ratio

Abstract

MEMS tunable capacitors have been fabricated in a thin-film technology for passive integration. Using a dual-gap relay-type design, continuous and reversible capacitance tuning with a tuning ratio up to 17 has been demonstrated, while requiring an actuation voltage of only 20 V. A quality factor of 150 to 500 has been measured in the frequency range of 1 to 6 GHz, making these devices very suitable as building blocks in many RF applications. These are the highest tuning ratio and quality factor reported to date for parallel-plate tunable capacitors.